add --count/-n flag

1 files changed, 29 insertions, 1 deletions

diff --git a/src/output/aggregators.rs b/src/output/aggregators.rs
index 83171eb..34ecea4 100644
--- a/src/output/aggregators.rs
+++ b/src/output/aggregators.rs
@@ -8,7 +8,11 @@
 //! an Aggregator must make sure that the data is protected by a mutex or similar.
 use super::{super::LogResult, formats::Format, sorting::Sorting};
 
-use std::{io::Write, sync::Mutex};
+use std::{
+    io::Write,
+    sync::atomic::{AtomicU32, Ordering},
+    sync::Mutex,
+};
 
 pub trait Aggregator: Sync {
     fn push_item(&self, item: LogResult, format: &dyn Format, stream: &mut dyn Write);
@@ -62,3 +66,27 @@ impl Aggregator for SortedOutput {
         stream.flush().unwrap();
     }
 }
+
+/// An aggregator that just counts how many logs have been found.
+#[derive(Debug)]
+pub struct CountingOutput {
+    counter: AtomicU32,
+}
+
+impl CountingOutput {
+    pub fn new() -> Self {
+        CountingOutput {
+            counter: AtomicU32::new(0),
+        }
+    }
+}
+
+impl Aggregator for CountingOutput {
+    fn push_item(&self, _: LogResult, _: &dyn Format, _: &mut dyn Write) {
+        self.counter.fetch_add(1, Ordering::SeqCst);
+    }
+
+    fn finish(self: Box<Self>, _: &dyn Format, stream: &mut dyn Write) {
+        writeln!(stream, "{}", self.counter.into_inner()).unwrap();
+    }
+}